This method is declared obsolete, because, after introduction of generics as early as of .NET v.2.0, non-generic methods depending on types simply make no sense, they are just too bad next to generic ones.
Beginning with NUnit 2.5, generic equivalents are available:
IsInstanceOf<T>
,
IsNotInstanceOf<T>
,
IsAssignableFrom<T>
and
IsNotAssignableFrom<T>
:
http://www.nunit.org/index.php?p=typeAsserts&r=2.5.1[
^].
So, use them, don't use the obsolete.
—SA